Nicolas Sarkozy yesterday set out to convince the French people that he is not the arrogant, highly strung, and over-ambitious hardman his critics paint him, vowing to lead France as a humbled and changed man.

With the latest polls showing that more than half the electorate are disturbed by him, the interior minister, who has been seen as authoritarian and desperate to appeal to the extreme right, launched an image makeover with his presidential bid amid the pomp of a glittering US-style rally in southern Paris.

The leader of France's centre-right ruling UMP party was officially anointed presidential candidate with 98% of the vote after nobody challenged him to an internal party race, prompting critics' comparisons with the "self-coronation" of another French leader of diminutive height and large ambition, Napoleon.

Like Napoleon, Mr Sarkozy has portrayed himself as a political outsider, far from the elite ruling class, who has emerged from a humble background to save France from itself. He has urged a clean break with decades of centre-right government and demanded an end to the French model of regulation, state interference and high public spending, praising the free market Anglo-Saxon approach. He yesterday promised a new France of unburdened entrepreneurs and a Thatcherite revolution of new, confident home owners.

But his reputation as a free marketeer has meant many voters, already anxious about jobs and living standards, fear his economic reform plans. Some blamed his harsh language for unrest on poor housing estates and for stoking riots, and his unashamed declaration that he was a "friend of America" has prompted socialists to warn he would turn France into a franchise of "the George Bush company".

But yesterday Mr Sarkozy attempted to bat off criticism with a new caring face for the two-round presidential elections in April and May, assuring the public he was opposed to the war in Iraq and would defend France on the international stage. He appeared sober-faced, avoiding his once-trademark confident grin, which had been seized on by cartoonists as demonic.

Ever the showman, he set the tone for his campaign by stepping out on a vast set created for him by the brains behind one of France's Pop Idol-style TV shows. With the tricolour projected behind him, he addressed 100,000 cheering fans transported from across France on special TGVs and coaches, many wearing stickers likening Sarkozy to Superman and T-shirts proclaiming "A new generation".

His advisers presented the €3.5m televised convention as the massive "rallying call of a united political family", but Mr Sarkozy was forced to try to smooth over the cracks left by his former mentor turned rival, Jacques Chirac, who is threatening to stoke a mini civil war within the ranks. Although Mr Sarkozy has the support of almost all his cabinet colleagues and UMP parliamentarians, President Chirac has left open the possibility that he could stand for a third term, as a candidate against Mr Sarkozy at the last minute. "I love Chirac, I vote Sarko," read the T-shirts worn by a delegation from Mr Chirac's heartland in Corrèze, who felt the president should step back and allow Mr Sarkozy to be the "voice of renewal".

"I have understood that humanity is a strength, not a weakness. I have changed," Mr Sarkozy told the crowd, explaining that he could relate to people struggling to find jobs and decent homes because he too had "suffered" rejection and failure.

The rally marked the official start of campaigning in the closest-run presidential election in recent history, that will pit Mr Sarkozy, long presented as the cocksure Alpha male who rose to ascendancy as France's "top cop", against the popular Socialist candidate, Ségolène Royal, France's first potential woman president, a mother of four who has positioned herself as a "caring voice", breaking with the arrogance of France's government by listening to the "citizens" who she feels "know best".

Neck and neck in the polls, both candidates claim to represent a break with the past needed to tackle France's mood of malaise. Twelve years under Chirac has left the country struggling to come to terms with youth unemployment, debt and the threat of economic stagnation.

Mr Sarkozy yesterday described his campaign as a battle for the soul of France, unveiling a new logo, "Together anything is possible", and pastoral image. As if to head him off at the pass, Ms Royal, whose logo also involves a similar image, ensured she spent yesterday in the countryside talking to farmers. While Mr Sarkozy, from the rich outskirts of Paris, has been portrayed as a city boy, Ms Royal has followed the lead of her former mentor, François Mitterrand, presenting herself as a woman at home in la France profonde

Signalling a desire to rise above his partisan past, Mr Sarkozy told the rally: "I must turn towards all the French people. I must unite them.

Him v Her:

Nicolas Sarkozy, 51, whose father was a Hungarian minor aristocrat, is the first son of an immigrant with a chance of becoming France's president.

By the age of 15, his ambition was to lead the country. His biographers suggest that his ruthless progress up the centre-right hierarchy was spurred by an unhappy childhood in a broken home.

A lawyer by profession, he served as mayor of the affluent Paris suburb of Neuilly from 1983 to 2002, then as interior minister and finance minister.

He is married and a father of three. His break-up and reconciliation with his second wife and adviser Cecilia was played out in the media. She choreographs his campaign behind the scenes.

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